U.S. patent application number 12/771641 was filed with the patent office on 2010-11-04 for cold-shrink separable connector.
This patent application is currently assigned to 3M Innovative Properties Company. Invention is credited to Nga K. Nguyen, Robert J. Schubert, William L. Taylor, Carl J. Wentzel.
Application Number | 20100279543 12/771641 |
Document ID | / |
Family ID | 43030726 |
Filed Date | 2010-11-04 |
United States Patent
Application |
20100279543 |
Kind Code |
A1 |
Nguyen; Nga K. ; et
al. |
November 4, 2010 |
COLD-SHRINK SEPARABLE CONNECTOR
Abstract
A cold-shrink article having a chamber with an enlarged interior
section to prevent the collapse of an end of a support core placed
in the chamber.
Inventors: |
Nguyen; Nga K.; (Austin,
TX) ; Taylor; William L.; (Round Rock, TX) ;
Wentzel; Carl J.; (Austin, TX) ; Schubert; Robert
J.; (Cedar Park, TX) |
Correspondence
Address: |
3M INNOVATIVE PROPERTIES COMPANY
PO BOX 33427
ST. PAUL
MN
55133-3427
US
|
Assignee: |
3M Innovative Properties
Company
|
Family ID: |
43030726 |
Appl. No.: |
12/771641 |
Filed: |
April 30, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61174632 |
May 1, 2009 |
|
|
|
Current U.S.
Class: |
439/521 |
Current CPC
Class: |
H01R 43/18 20130101;
H01R 13/53 20130101 |
Class at
Publication: |
439/521 |
International
Class: |
H01R 13/52 20060101
H01R013/52 |
Claims
1. An article comprising: a cold-shrink housing having a first
chamber that intersects with a second chamber, the first chamber
having a generally cylindrical shape with an upper portion nearest
the second chamber, the upper portion having a diameter greater
than the diameter of the remainder of the first chamber.
2. The article of claim 1 wherein the first chamber and second
chamber intersect to form an L-shaped opening.
3. The article of claim 1 wherein the first chamber and second
chamber intersect to form a T-shaped opening.
4. The article of claim 1 wherein the maximum increase in the inner
diameter of the upper portion when a removable support core is
loaded within the first chamber is less than 100% of the inner
diameter absent the removable support core in the first
chamber.
5. The article of claim 4 wherein the maximum increase in the inner
diameter of the upper portion when a removable support core is
loaded within the first chamber is equal to or less than about 20%
and greater than 0% of the inner diameter absent the removable
support core in the first chamber.
6. The article of claim 1 wherein the upper portion of the first
chamber and the remainder of the first chamber experience a
differential increase in inner diameter when a removable support
core is loaded into the first chamber.
7. The article of claim 6 wherein the maximum increase in the inner
diameter of the upper portion when a removable support core is
loaded within the first chamber is between about 100% and about,
but greater than, 0% of the inner diameter absent the removable
support core in the first chamber and the maximum increase in the
inner diameter of the remainder of the first chamber when a
removable support core is loaded within the first chamber is
between about 150% and about 300% of the inner diameter absent the
removable support core in the first chamber
8. The article of claim 1 further comprising a removable support
core within the first chamber, wherein the outer diameter of the
removable support core is larger than the inner diameters of both
the upper portion and the remainder of the first chamber in its
relaxed state.
9. The article of claim 1 wherein the portion of the housing
surrounding the first chamber comprises an outer semi-conductive
layer, an intermediate insulating layer and an inner
semi-conductive layer.
10. The article of claim 1 further comprising a cable assembly in
the first chamber of the housing.
11. The article of claim 8 further comprising a cable assembly in
the first chamber of the housing wherein the inner semi-conducting
layer of the housing makes intimate contact with a connector
portion of the cable assembly.
12. The article of claim 11 wherein the inner semi-conducting layer
of the housing further makes intimate contact with a cable
insulation portion of the cable assembly.
13. The article of claim 8 wherein the outer semi-conducting layer
of the housing makes intimate contact with an insulation shield
portion of the cable assembly.
14. The article of claim 1 wherein the housing comprises an
elastomeric silicone.
15. The article of claim 14 wherein each of the outer
semi-conductive layer, intermediate insulating layer, and inner
semi-conductive layer comprise an elastomeric silicone.
16. The article of claim 8 wherein the outer diameter of the
removable support core varies along its length, and wherein the
outer diameter of each portion of the core is greater than the
inner diameter of the adjacent portion of the first chamber.
17. The article of claim 11 wherein the outer conducting layer
further makes intimate contact with a metallic ground of the cable
assembly at the open end of the first chamber.
18. The article of claim 17 wherein metallic ground is a tape or
wire layer.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional
Patent Application 61/174,632, filed May 1, 2009.
TECHNICAL FIELD
[0002] This invention relates to a cold-shrink cable termination
system.
BACKGROUND
[0003] A cable termination system typically includes a cable
terminated with a metallic lug (i.e., cable connector), the cable
connector and end portion of the cable being inserted into the
housing of a connecting device, the cable connector being connected
to a mating device within the confines of the housing. The housing
needs to form a tight seal around the end portion of the cable to
prevent contamination or corrosion of the connection.
[0004] A problem that arises with cable termination systems is that
the internal diameter of the housing has to be adapted to the
diameter of the cable. Cable sizes vary so it's necessary to have
either several connecting devices of different sizes, each being
designed to fit exactly the diameter of the particular cable, or
several adapters of different thicknesses, each adapter enabling
the housing to be adapted to a cable of a given diameter. These
solutions are costly because they require a large number of
connecting devices or adapters to adapt to a whole range of
cables.
[0005] Another known solution is to provide a cold-shrink housing
that can be expanded over almost its entire length to receive
cables having a range of diameters. When a cold-shrink housing is
used, a removable support core is placed within a portion of the
housing. The removable support core has an outer diameter that is
larger than the inner diameter of the housing portion when it is in
a relaxed state. The removable support core holds the housing in an
expanded state until the cable end and lug are inserted into the
housing. The core is then removed, allowing the cold shrink housing
to tighten around the cable.
[0006] A problem with the cold-shrink cable termination system is
that the end of the removable support core placed within the
housing cannot withstand the excessive pressure placed upon them by
the expanded housing and will often collapse. Prior art references
have sought to address this problem by reinforcing the ends of the
removable support core.
SUMMARY
[0007] The present invention seeks to address the issue of core
collapse caused by the excessive pressure of an expanded housing.
However, unlike prior art solutions, the present invention focuses
on the housing rather than the core.
[0008] The present invention features a novel article comprising a
cold-shrink housing having a first chamber that intersects with a
second chamber, the first chamber having a generally cylindrical
shape with an upper portion nearest the second chamber, the upper
portion having a diameter greater than the diameter of the
remainder of the first chamber.
[0009] An advantage of at least one embodiment of the present
invention is that it reduces the amount of pressure exerted on an
end of a cold-shrink support core inserted furthest into a
connecting device housing, thereby reducing the likelihood of core
collapse.
[0010] Another advantage of at least one embodiment of the present
invention is that the semi-conductive layer on the interior of the
first chamber of the connecting device makes intimate contact with
the cable connector.
[0011] An advantage of at least one embodiment of the present
invention is that the outer semi-conductive layer provides an
integrated ground because it makes contact with the cable metallic
ground layer.
[0012] An advantage of at least one embodiment of the present
invention is that the cold-shrink connecting device eliminates the
need for a cable adapter. This eliminates an electrical interface,
which can fail.
[0013] The above summary of the present invention is not intended
to describe each disclosed embodiment or every implementation of
the present invention. The Figures and detailed description that
follow below more particularly exemplify illustrative
embodiments.
BRIEF DESCRIPTION OF DRAWINGS
[0014] FIG. 1 depicts a typical cable assembly suitable for use
with the present invention.
[0015] FIG. 2 depicts an embodiment of the connecting device of the
present invention.
[0016] FIG. 3 depicts an embodiment of the connecting device of the
present invention with a removable support core loaded in the
connecting device.
[0017] FIG. 4 depicts an embodiment of the connecting device of the
present invention with a cable assembly in the connecting
device.
DETAILED DESCRIPTION
[0018] In the following detailed description of the preferred
embodiments, reference is made to the accompanying drawings that
form a part hereof. The accompanying drawings show, by way of
illustration, specific embodiments in which the invention may be
practiced. It is to be understood that other embodiments may be
utilized, and structural or logical changes may be made without
departing from the scope of the present invention. The following
detailed description, therefore, is not to be taken in a limiting
sense, and the scope of the invention is defined by the appended
claims.
[0019] FIG. 1 shows a standard power cable assembly 20 which
includes cable connector 22 attached to a cable 24. Cable 24
includes cable conductor 26 concentrically surrounded by cable
insulation 28, cable insulation shield 30, cable metallic ground
32, and cable jacket 34. To form cable assembly 20, each of the
cable insulation 28, cable insulation shield 30, cable metallic
ground 32, and cable jacket 34 are stripped back from and end of
cable 24 to expose a portion of the underlying layer, down to cable
conductor 26. Cable connector 22 is then attached to the exposed
portion of cable conductor 26 by any suitable means, typically by
crimping.
[0020] FIG. 2 shows connecting device 100 which includes housing
102 that generally defines first chamber 104 and second chamber
106. First chamber 104 and second chamber 106 intersect such that
the interior of first chamber 104 is in communication with the
interior of second chamber 106. First and second chambers 104,106
may intersect to form a general T-shape as shown in FIG. 2 or a
general L-shape (not shown). First chamber 104 further includes an
upper portion 108 located nearest to second chamber 106. As can be
seen in FIG. 2, the inner and outer diameter of upper portion 108
of chamber 104 are larger than the inner and outer diameters of the
remainder of first chamber 104. Housing 102 may further include an
outer semi-conductive layer 110 and an intermediate insulating
layer 112, with the interior wall of first chamber 104 being at
least partially covered by inner semi-conductive layer 114.
[0021] Housing 102 may be made from any material suitable for
cold-shrink applications. Most suitable are materials such as a
highly elastic rubber material that has a low permanent set, such
as ethylene propylene diene monomer (EPDM), elastomeric silicone,
or a hybrid thereof. The semi-conductive and insulating materials
may be made of the same or different types of materials. The
semi-conductive and insulating materials may have differing degrees
of conductivity and insulation based on the inherent properties of
the materials used or based on additives added to the
materials.
[0022] To enable cable assembly 20 to be inserted into first
chamber 104 of connecting device 100, a removable support support
core 200 is first loaded into first chamber 104, as illustrated in
FIG. 3. Once loaded, removable support support core 200 typically
extends from the end of the upper portion 108 nearest the second
chamber 106 to beyond the open end 109 of first chamber 104 through
which cable assembly 20 is inserted. When loaded into first chamber
104, removable support support core 200 radially expands first
chamber 104 to an inner diameter greater than the outer diameter of
the largest portion of cable assembly 20 that will be inserted into
first chamber 104.
[0023] Removable support support core 200 may be made of any
suitable material and in any suitable configuration, but typically
consists of an extruded nylon or propylene ribbon that is helically
wound. To remove removable support support core 200 from first
chamber 104, removable support support core is unraveled by pulling
on a tab (not shown) extending from one end of the removable
support support core 200 and causing separation of the core along
the helical score line. Preferably, removable support core 200 is
unraveled starting with the end in upper portion 108 nearest the
second chamber 106 and ending with the end that extends beyond the
open end 109 of first chamber 104. Unraveling removable support
support core 200 in this manner prevent the open end 109 of first
chamber 104 from prematurely collapsing and obstructing the removal
of removable support support core 200.
[0024] When an end of a removable support support core is located
in the interior of a chamber as in the present invention, it is
possible that the pressure exerted by the expanded chamber on the
end of the core in the chamber will cause the end of the removable
support support core to collapse. The present invention addresses
this issue by providing an upper portion 108 of the first chamber
that has a larger inner and outer diameter than the remainder of
the chamber. With this feature, the upper portion 108 of the first
chamber is required to expand less than in a prior art connector
devices not having this feature, and therefore, less pressure is
exerted upon the end of the removable support core in the interior
of the chamber, compared to similar prior art connector
devices.
[0025] Preferably the inner diameter of the upper portion 108 of
first chamber 104 is of a size in comparison to the outer diameter
of a removable support core 200 inserted into first chamber 104
such that the maximum increase in the inner diameter of the upper
portion 108 when removable support core 200 is loaded within first
chamber 104 is less than 100%, and more preferably equal to or less
than about 20% and greater than 0%, of the inner diameter absent
removable support core 200 in first chamber 104.
[0026] The difference in inner diameter of the upper portion 108
and remainder of first chamber 104 will typically cause the upper
portion 108 and the remainder of the first chamber to experience a
differential increase in inner diameter when a removable support
core is loaded into the first chamber. In other words, the inner
diameter of the upper portion 108 will be required to increase less
than the inner diameter of the remainder of the first chamber to
accommodate a removable support core 200. This is particularly true
when the removable support core 200 has a constant outer diameter,
but may also be true when the removable support core has a tapered
or stepped shape. Regardless of the shape of the removable support
core 200, it is desirable that the outer diameter of the removable
support core 200 is larger than the inner diameters of both the
upper portion and the remainder of the first chamber in its relaxed
state so that inner surface of the first chamber 104 exerts at
least a sufficient amount of pressure on the removable support core
200 to keep it from dislodging from the first chamber 104. If the
outer diameter of the removable support core 200 varies along its
length, as with a tapered or stepped core, preferably the outer
diameter of each portion of the removable support core 200 is
greater than the inner diameter of the adjacent portion of the
first chamber 104.
[0027] Preferably, the maximum increase in the inner diameter of
the upper portion when a removable support core is loaded within
the first chamber is between about 100% and about, but greater
than, 0% of the inner diameter absent the removable support core in
the first chamber and the maximum increase in the inner diameter of
the remainder of the first chamber when a removable support core is
loaded within the first chamber is between about 150% and about
300% of the inner diameter absent the removable support core in the
first chamber.
[0028] Once the removable support core has been loaded into the
first chamber 104, cable assembly 20 may be inserted into first
chamber 104. Typically, cable connector 22 will include an aperture
23 at its free end. The free end is positioned in the intersection
of the first and second chambers, 104, 106 with the remainder of
the cable connector residing in the upper portion, and an adjacent
portion of chamber, of first chamber 104. Once the cable assembly
is correctly positioned, a stud (not shown) may be inserted through
aperture 23 and one or more mating devices 42 may be inserted into
second chamber 106 and attached to, or held in position against,
cable connector 22 by the stud. Removable support core 200 may then
be removed as described above to cause first chamber 104 to
contract and form a tight seal around cable assembly 20.
[0029] As shown in FIG. 4, when the connecting device has been
fully assembled, the inner semi-conducting layer 114 on the
interior wall of the first chamber 104 of the housing 102 makes
intimate contact with the cable connector 22 of cable assembly 20.
Preferably, the inner semi-conducting layer 114 also makes intimate
contact with the cable insulation 28 of cable assembly 20. A
portion of the interior wall of first chamber 104 is made of the
intermediate insulating layer 112. This portion preferably makes
intimate contact with cable insulation 28. A portion of the
interior wall of first chamber 104 is made of outer semi-conducting
layer 110. This portion preferably makes intimate contact with
cable insulation shield 30, and typically also makes intimate
contact with cable metallic ground 32, which may be a tape or wire
layer. The portion of the interior wall of first chamber 104 made
of the outer semi-conducting layer 110 preferably also makes
intimate contact with a portion of cable jacket 34 to prevent
contaminants and/or moisture from entering the first chamber
104.
[0030] Although specific embodiments have been illustrated and
described herein for purposes of description of the preferred
embodiment, it will be appreciated by those of ordinary skill in
the art that a wide variety of alternate and/or equivalent
implementations may be substituted for the specific embodiments
shown and described without departing from the scope of the present
invention. This application is intended to cover any adaptations or
variations of the preferred embodiments discussed herein.
Therefore, it is manifestly intended that this invention be limited
only by the claims and the equivalents thereof
* * * * *